The present invention relates to tamper evident container closures, and more specifically to such a closure for attachment to disposable containers designed to dispense potable liquids such as milk or juice.
Conventional containers used for dispensing beverages are often made from a flat blank of paperboard, the outside surface of which is coated with a plastic such as polyethylene to give it strength and make it liquid impervious. Many such containers are provided with a gabled upper end. Such gabled containers often include an integral paper spout folded into a front or rear portion of the gable and designed to be folded out as the carton is opened for dispensing the contents.
A major drawback of such a spout is that the only way to reclose the container is to fold in the spout, which does not totally reseal the container. Thus there is a potential for premature spoilage of the container contents. A further drawback of such a spout is that for liquids which must be shaken prior to use, previously opened containers equipped with folded in spouts are prone to spillage of the contents upon shaking.
A preferred design criterion of such containers is that they be tamper evident. This objective is accomplished in the internal spout containers by inspecting the condition of the spout to determine if the container has been opened previously.
Attempts to address these drawbacks and design criterion have focused on the provision of a plastic spout having a removable cap as well a threaded pointed end designed for puncturing an opening in the container. Once the pointed end pierces the container, the threaded end is inserted into the container until the spout is properly seated. The disadvantages of this type of closure include increased piece part costs from more sophisticated tooling, as well as the extra material used for the threaded, pointed piercing end. Another disadvantage of such a closure is that the pointed end may not provide an adequate seal for the opened container.
Other attempts at addressing the above-identified drawbacks relate to attaching spouts or pull tabs to the container with adhesive. These closures include an integral snap fit plastic formation for reclosing the opening or spout. Although these latter spouts are not as expensive to produce as the piercing tip versions identified above, they are prone to the entire closure becoming detached from the container as the user pulls the tab upon opening the container.
Thus, there is a need for a tamper evident reclosable spout type closure for containers designed to dispense portable liquids, where the closure is effective in resealing the container after the initial opening. There is also a need for such a closure which is reliably secured to the container and is economical to produce.